Which case resulted in the ruling that intelligence tests could not be used to place black children in special classes in california?

I believe the answer is: Larry P. v. Riles (1979).

The decision was based on the findings that Intelligence test could be influenced by both genetics and environment. For minorities who do not have access to good nutrition and good education since early age, the intelligence test is deemed as unfair.

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.